Halo azido naphthalenes

ABSTRACT

Novel halo azido naphthalenes and dry photoimaging processes and compositions employing said naphthalenes are disclosed.

United States Patent Singh [4 1 Oct. 17, 1972 [54] I HALO AZIDO NAPHTHALENES [56] References Cited [72] invent or: Balwant Singh, Stamford, Conn. UNITED STATES PATENTS [731 Assign America" Cyanamid m 3,324,148 6/1967 Cotter ..260/349 Stamford, Conn.

[22] Filed; May 2 1971 Primary Examiner-John M. Ford Attorney-Robert P. Raymond [21] Appl. No.: 147,117

- Y [57] I ABSTRACT [52] US. CL, .,....260/ 349, 96/49, 96/91 N, Novel halo azido naphthalenes and dry photoimaging 96/27 processes and compositions employing said [51] Int. Cl ..C07c 117/00 naphthalenes are disclosed Field of Search ..260/349 3 Claims, 1 Drawing Figure WJVELENGTH A (nml HALO AZIDO NAPHTHALENES This invention relates to certain novel halo azido naphthalenes and todry photoirnaging processes and compositions employing said compounds.

Photosensitive compounds, compositions and processes play an essential role in photography and the related arts dealing with the formation of images with the aid of some activatinginfluence, such as light, heat,

etc. For many applications, as in the case of printing on white paper, it is desirable to maximize the neutrality of the image, in addition to achieving good color stability, speed, acuity, resolution and tonal range as well as to achieve the convenience of a dry imaging process em-v ploying relatively inexpensive materials.

Accordingly, it is an object of the present invention to provide photosensitive compositions which are suitable for the formation of images having broad spectral characteristics as well as good image stability, acuity, resolution and tonal range. It is a further object to provide'a convenient, dry photoimaging process for the formation of such images. These and other objects of the present invention will become apparent from the description and examples which follow. 7

In copending application Ser. No. 82,129, filed Oct. 19., 1970, the use of 1,8-diazidonaphthalene and8- azido-l-naphthylamine in photoimaging was disclosed.

It has been unexpectedly found that images of enhanced neutrality and optical density can be achieved by employing the novel halo azido naphthalenes selected from the group consisting of:

wherein Y is a member selected from the group consisting of -N and NH While Applicant does not wish to be limited to a I specific theory, it is believed that the halo substituents solvent wherein X is Cl or'Br.

The corresponding dihalo l,8-di azidonaphthalenes can be readily formed by converting the amine function to an azide function by conventional procedures such as those disclosed, for example, in U. S. Pat. No. 3,123,621. 7

The novel, photosensitive compounds of the present invention are 8-azido-2,4-dibromo-l-naphthylamine, 8-azido-2,4-dichlorol -naphthylamine, 1,8-diazido- 2,4-dibromonaphthylamine and l ,8-diazido-2 ,4- dichloronaphthylamine.

The photosensitive compositions of the present invention comprise a suitable photographic substrate having a photosensitive film or coating deposited thereon. The coating is composed of conventional filmforming plastics having one or more of the above photosensitive compounds uniformly incorporated (preferably dissolved) therein.

Suitable substrates include, for example, such materials as paper, plastic, wood, metal and glass.

. Among the suitable conventional polymeric binders,

one may mention, for example, polyvinyl chloride,

polyethylene, polymethylmethacrylate, polyvinyl acetate, cellulose acetate, copolymers of the corresponding monomers, copolymers of vinylidene chloride and acrylonitrile and mixtures of the above polymers.

Incorporation of the photosensitive compounds within the film-forming polymer can be conveniently achieved by selecting an organic solvent in which both the polymer and photosensitive compound are soluble. Suitable solvents include for example toluene, tetrahydrofuran, benzene, methyl ethyl ketone, mixtures of the above and the like. The resulting solution can be applied to the substrate of choice by a variety of standard coating techniques.

Of the suitable methods of applying the sensitized dope to the structure, the Fixed Blade Method, the Imbibing Method and the Meyer Rod Method are among the preferred techniques.

In the Fixed Blade Method, the base material is positioned under a fixed blade and an excess of the coating material is placed on the base. The base is then passed under the blade to produce a uniform coating having a thickness determined by the distance between the mounted blade and the base material.

In the imbibing Method, a base stock having a plastic surface is coated with the active compound by passing it under a roller, touching a solution of the azido compound. The excess coating is removed from the surface by an air knife. By way of illustration, one may mention passing paper coated with polyvinyl chloride, polyvinyl acetate or polymethylmethacrylate through a solution of l,8-diazido-2,4-dibromonaphthalene in a solvent such as tetrahydrofuran, methyl ethyl ketone, acetone or toluene or mixtures thereof.

In the Meyer Rod Method, the coating composition is placed at one end of the base material and a metal rod wound with fine wire is passed through the liquid causing it to be spread over the surface of the base material. The thickness of the coating produced by this method is determined by the size of the wire used in the winding.

Preparation of the photosensitive composition is completedby merely removing the solvent from the photosensitive film by evaporation.

The concentrations of the photosensitive compound and thickness of the coating applied to the substrate may be varied to tailor the photosensitive system so as to achieve the desired degree of image intensity, speed, etc. Optimum concentrations and thicknesses will, of course, vary depending upon the particular photosensitive compound, binder material, coating thickness, temperature, time, and other factors. In general, satisfactory photoimages can be produced by employing binder compositions having from about to about 20 percent by weight of the photosensitive compound and. coatings having thicknesses in the range of from about 0.05 to about 1.50 mils. Preferred concentrations and thicknesses are about percent by weight and about 0.3 mils, respectively.

The aromatic azido compounds are themselves generally sensitive to radiation containing wavelengths within the ultraviolet region. By means of the addition of a sensitizing agent to the polymer binder, the sensitivity can be extended into the range of from-360 mp. to 470mg. or greater. The energy transfer of such systems is surprisingly efficient in view of the typically high viscosity of the binder polymer systems being sen sitized.

Several advantages are provided by the use of sensitized. systems. They permit the use of apparatus equipped with inexpensive and convenient light sources, such as incandescent lamps, and allow projection printing through various optical systems with normal optical glass. They also permit the simultaneous use of both direct and indirect excitation of azido compounds through simultaneous exposure of the photosensitive compounds to both visible and ult'raviolet light. Alternatively, enhanced absorption can be achieved by using an ultraviolet absorbing sensitizer in combination with the azido composition.

I the abovementioned light table.

Suitable Sensitizers include, for example, fluoranthene, thioxanthone, fluorenone, perylene, benzanthrone, benzophenone, phenazine and thioacridone.

Sensitizers whichabsorb light in the visible spectrum are of necessity colored compounds. Where the colors caused thereby are found to be'objectionable, one may employ a colorless,, ultraviolet absorbing sensitizeror a volatile sensitizer, such as, fluorenone, in a gas permeable binder, suchas, polyvinyl chloride. The period and degree of heat treatment is adjusted to be sufficient to effect volatilization of the fluorenone without producing excessive background colorup.

Optimum relative concentrations of the sensitizer and azido compound will, of course, vary with the particular system being employed. Generally, energy transfer is favored by high concentrations of .the photosensitive compound. It is preferred to employ the sensitizer in a sufficient concentration to absorb the incident light. However, excessively high concentrations of the sensitizer will cause complete absorption of the incident light at the surface of the plastic matrix and traviolet-rich fluorescent lamps, such as, 15 Watt Black Light, No. Fl5T8-BL by General Electric and Rayonet Photochemical Reactor Lamps, No. RPR 3000A by The Southern New England Ultraviolet Company provides a convenient source of activating radiation. Conventional azo printing machines, equipped with high pressure mercury vapor lamps may also be employed.-

Since they emit both visible and ultraviolet light, they are especially well adapted for use with those compositions having Sensitizers to visible light.

Absorption of incident light can be maximized by matching the frequencies of the incident light with the absorption frequencies of the photosensitive compound or the sensitizer if one is employed.

Patterning of the activating radiation can generally 7 be achieved by any of the conventional methods. Suitable methods include passing the light through a film transparency or a template, use of-a cathode ray tube containing an ultraviolet phosphor, such as, a Litton lndustries, Inc. Cathode Ray Tube, Ser. No.4188, which contains a P16 phosphorj and using an ultraviolet pen light, such as Ultraviolet Products, Inc. Pen Light, or ultraviolet laser, such as might be used in spatial frequency modulation and storage, etc.

Optimum periods of irradiation will'vary widely, depending upon the particular photosensitive composition, opaci'ty of transparency, and light source employed. Exposure for a few seconds in a conventional azo printer is generally adequate while periods of two minutes or more may be required for a source such as The enhancement of image neutrality and optical density produced by the presence of the halo substituent is shown in FIG. 1. These characteristics were observed by irradiating polyester film substrates (Mylar by E. I. duPont deNemours) uniformly coated with a layer of polyvinyl chloride (Geon 101, d 1.4, by The B. F. Goodrich Chemical Company) having a thickness of from about 0.2 to about 0.3 mil which was LON in one of the following photosensitive compounds: 8- azido'2,4-dibromo- 1 -naphthylamine, l,8-diazido-2 ,4- dibromonaphthylamine, 8-azido-l-naphthyla'mine and l,8-diazidonaphthylamine. Imaging was achieved by exposure through a film transparency to a bank of black light fluorescent lamps transmitting light in the 300-380 n.m. (peaking at 350 n.m.) region for a period of from about 10 to about 30 seconds. The result was a gray-black image of excellent tonal range, resolution and acuity in each case. However, the image neutrality and optical. density were in each case substantially enhanced by the presence of the halo substituent.

The processes and compositions of the present invention are further illustrated by' the following examples which are not to be taken as limitative thereof. All parts and percentages herein are by weight unless otherwise indicated.

EXAMPLE 1 1-Amino-8-azido-2,4 Dibrom0naphthylamine Azido- A solution of 1-amino-8-azidonaphthylamine (2.3 g., 0.0125 mole) in ml. of glacial acetic acid was treated with a solution of bromine (4.0 g., 0.025 mole) in 50 ml. of glacial acetic acid. The precipitated.

halographic information EXAMPLE 2 l,8-Diazido-2,4-Dibromonaphthylamine A solution of l-amino8-azido-2 ,4-

dibromonapthylamine (500 mg, 1.46 moles) in 50 ml. 1

of acetic acid was mixed with ml. of concentrated hydrochloric acid and cooled to 5 C. in an ice'bath. A solution of NaNO (280mg, 0.4 mole) in water (1 ml.) was added dropwise with stirring. After /2 hour, the mixture was poured into an excess of NaN;, (2 g., in 100 ml. of ice-water mixture). The precipitate of the diazide was removed by filtration, dissolved in ethyl ether, dried over anhydrous MgSO and filtered through charcoal. Removal of the ether left the desired product as a residue. It was recrystallized from n-hexane to yield 334 mg. (63 percent), m.p. l30132 C. Identification was made by infrared and elemental analysis:

Calcd. for C H N Br C, 32.60; H, 0.90; N, 22.80; Br, 43.50. Found: C, 32.85; H, 0.84; N, 23.00, Br, 43.75.

EXAMPLE 3 The enhancement of optical density produced by the halo substituents is demonstrated by the following tests.

Photosensitive compositions were prepared by uniformly coating polyester film substrates (Mylar) withlayers of polyvinyl chloride (Geon 101) which were 0.7N in the photosensitive compound. The films were imaged by exposing them through a film transparency to a bank of black light fluorescent lamps transmitting light in the 300-380 n.m. (peaking at 350 n.m.) region for various equal intervals of time. The films were thereafter heated in an oven at C. for 60 seconds and the optical density of each film was thereafter measured. In each case, as shown by the data presented in Table 1 below, the bromo substituents produce about 50 percent increases in efficiency.

TABLE I Exposure Time 1,8-Diazidonaphthalene" l,8-Diazido-2,4-

(min.) (OD) dibromonaphthalene Thickness of coating 0.2 mil Iclaim: I. A compound selected from the group consisting of:

and

l 3r (ill wherein Y is a member selected from the group consisting of N and NH 2. The compound according to claim 1: 8-azido-2,4- dibromo- 1 -naphthylamine.

3. The compound according to claim 1: 1,8-diazido- 2,4-dibromonaphtha1ene. 

2. The compound according to claim 1: 8-azido-2,4-dibromo-1-naphthylamine.
 3. The compound according to claim 1: 1,8-diazido-2,4-dibromonaphthalene. 